1. Field of the Invention
The present invention relates to assemblable and disassemblable frame structures such as used for tents, awnings, canopies and the like, and more particularly relates to such structures which utilize conventional junction elements and compound tube beam and rafter components enabling relatively greater spans and relatively simpler construction than is possible with conventional single tube beam and rafter components.
2. Description of the Prior Art
Conventional tent, awning and canopy frame structures of a readily assemblable and disassemblable nature such as utilized in the rental trade are commonly made up of cylindrical tubing and various types of junction elements or connectors, or so-called slip fit or slip-on fittings, commonly termed corner, ridge intermediate, intermediate, three-way crown, four-way crown, six-way crown and eight-way crown fittings, fabricated of 1.66" OD aluminum or steel tubing. To assemble a given desired structure, it is conventional to use 2" OD cylindrical tubing with 1/8" inch wall thickness in appropriate lengths to make up the uprights (suitably in 7'8" lengths), eave beams (suitably in 9'4", 14'4" and 19'4" lengths) and hip rafters (suitably in 6'10", 10'6", 14'4", 21'10" and 29'4" lengths) and, where used, intermediate rafters (suitably 5', 10'6", 16'1" and 21'8" lengths) with the various rafters being interconnected by a crown fitting at the ridge or peak or peaks or by corner or intermediate fittings at the eave beams. Conventionally, also, the tubes and fittings are joined together in a telescoping manner with the tubes telescoped over associated arms of the fittings and the tubes and fittings are interlocked together by so-called locking quick pins. With such conventional single tube constructions, it is common to limit the span between uprights to ten feet, i.e. limit the length of the eave beams to 9'4" so that the structure had adequate strength to withstand unusual loads, windstorms or the like with an adequate safety margin. It is also known to use single tube eave beams of 14'4" length in certain light duty applications. However, when sturdy tent, awning or canopy structures are desired of relatively larger area coverage, the assemblage becomes quite complicated with need oftentimes for additional internally placed supporting components.
Crow U.S. Pat. No. 1,958,296 discloses tent frames providing an increased span between corner posts by use of arched braces, also called trusses, which in general are made up of laterly spaced top and bottom chords interconnected by spaced struts.
In general it is also known as in Dithridge U.S. Pat. No. 426,558 to construct "beams or sills for railway-cars" with tubular edges and with one or more connecting plates therebetween and with the one or more connecting plates arranged essentially coplanar with the axial centers of the tubular edges, but without any suggestion of utilization of any similar compound tubular configuration in readily assemblable and disassemblable structures such as the structures to which the present invention applies.